Cactus V4 Sync Speed

Bsimon

Hey all,

I have been using my V4's strictly for product shoots with lower shutter speeds in the studio.

HOWEVER

Tonight I decided to experiment with their max sync speed on my D90 outdoors with a single sb600. Since it was fairly sunny I had trouble using my commander flash on my D90 and needed these.

I found the fastest sync speed I could achieve was 1/250th. I know these can be effective at up to 1/600th with a max of 1/1000th. I am wondering why I cannot achieve better than 1/250th??

Only thing I can think is my AAA's may be around 75% though I highly doubt it.

Anyone else have experience with this phenomenon?

Thanks in advance!

Dan7312

To go over 1/250 I'm pretty sure you will need to use high speed sync (that's what it is called on Canon, don't know what it is called on Nikon).

I'm pretty sure the Nikon opitical link works like the Canon one, the optical signal tells the flash to go into high speed sync if the shutter is over a certain speed.

I think that cactus just sends a pulse that tells the flash to fire, but doesn't include any info that tells it to use high speed sync. Maybe you can set it manually on the flash?

Bsimon

Dan,

Thanks for responding. On nikon, as far as I know, high speed sync is called fp and will work up to 1/2000th with the on camera flash in comander mode controling a speedlight compatible with cls.

I have fp turned on.

Maybe 1/250th is the best my set can muster??

ziggy53

Bsimon wrote: »

Dan,

Thanks for responding. On nikon, as far as I know, high speed sync is called fp and will work up to 1/2000th with the on camera flash in comander mode controling a speedlight compatible with cls.

I have fp turned on.

Maybe 1/250th is the best my set can muster??

When you use a radio master/slave like the Cactus units the host camera only sees the transmitter as a simple flash unit and, like Dan said, the camera reverts to basic flash operation and sync speed. When you use a radio unit the commander/wireless capability is defeated unless you happen to use an advanced unit like the PocketWizard Flex/Mini combinations.

Dan7312

I don't use Cactus, but I did a quick check of the spec's for them an they only work up to the max sync speed of the camera. Beyond the max sync speed the flash has to be in high speed sync mode to work and Cactus has no way to kick the flash into that mode.

I think max sync speed for Nikon is the same as for Canon, 1/250.

So bottom line is that it looks like Cactus doesn't support high speed sync.

PocketWizards and RadioPoppers radio triggers support high speed sync . There may be others but I'm not familiar with them.

time2smile

change your E5 setting and try again...
the ebay RF602 do support